Disposable syringes are in widespread use for a number of different types of applications. For example, syringes are used not only to withdraw a fluid (e.g., blood) from a patient but also to administer a medication to a patient. In the latter, a cap or the like is removed from the syringe and a unit dose of the medication is carefully measured and then injected or otherwise disposed within the syringe.
As technology advances, more and more sophisticated, automated systems are being developed for preparing and delivering medications by integrating a number of different stations, with one or more specific tasks being performed at each station. For example, one type of exemplary automated system operates as a syringe filling apparatus that receives user inputted information, such as the type of medication, the volume of the medication and any mixing instructions, etc. The system then uses this inputted information to disperse the correct medication into the syringe up to the inputted volume.
In some instances, the medication that is to be delivered to the patient includes more than one pharmaceutical substance. For example, the medication can be a mixture of several components, such as several pharmaceutical substances.
By automating the medication preparation process, pharmacies achieve better accuracy, better cleanliness, and improved production and efficiency. This results in reduced production costs and also permits the system to operate over any time period of a given day with only limited operator intervention for manual inspection to ensure proper operation is being achieved. Such a system finds particular utility in settings, such as large hospitals, including a large number of doses of medications that must be prepared daily. Traditionally, these doses have been prepared manually in what is an exacting but tedious responsibility for a highly skilled staff. In order to be valuable, automated systems must maintain the exacting standards set by medical regulatory organizations, while at the same time simplifying the overall process and reducing the time necessary for preparing the medications.
Because syringes are used often as the carrier means for transporting and delivering the medication to the patient, it is advantageous for these automated systems to be tailored to accept syringes. However, the previous methods of dispersing the medication from the vial and into the syringe were very time consuming and labor intensive. More specifically, medications and the like are typically stored in a vial that is sealed with a safety cap or the like, under which is a penetrable membrane or septum. In conventional medication preparation, a trained person retrieves the correct vial from a storage cabinet or the like, confirms the contents and then removes the safety cap manually. This is typically done by simply popping the safety cap off with one's hands. Once the safety cap is removed, the trained person inspects the integrity of the septum and cleans the septum with a disinfectant, for example, 70% isopropyl alcohol. A sharp, hollow sterile instrument, e.g., a needle attached to a syringe, is then used to pierce the septum and withdraw the desired amount of medication from the vial into the syringe. The withdrawn medication is then placed into a container (e.g., another syringe) to permit subsequent administration of the medication to a patient. In some instances, the original syringe is used as the medication administration container.
A conventional syringe includes a barrel having an elongated body that defines a chamber that receives and holds a medication that is disposed at a later time. The barrel has an open proximal end with a flange being formed thereat and it also includes an opposing distal end that has a barrel tip that has a passageway formed therethrough. The passageway terminates in an outer surface of the barrel tip that conforms to the specification for a male luer fitting and can include features to permit closure of the passageway with a cap. As previously mentioned, the term “medication” refers to a medicinal preparation for administration to a patient and most often, the medication is contained within the chamber in a liquid state even though the medication initially may have been in a solid state, which was processed into a liquid state. The syringe further includes a plunger that is removably and adjustably disposed within the barrel.
Drugs intended for injection must be in a liquid state. Many drugs intended for injection are initially provided of the shelf in solid (powdered) form within an injectable drug vial that is initially stored in a drug cabinet or the like. To prepare an injectable unit dose of medication, a prescribed amount of diluent (water or some other liquid) is added to the vial to cause the solid drug to go completely into solution. Mixing and agitation of the vial contents is usually required. This can be a time consuming and labor intensive operation since first it must be determined how much diluent to add to achieve the desired concentration of medication and then this precise amount needs to be added and then the vial contents need to be mixed for a predetermined time period to ensure that all of the solid goes into solution. Thus, there is room for human error in that the incorrect amount of diluent may be added, thereby producing medication that has a concentration that is higher or lower than it should be. This can potentially place the patient at risk. The reconstitution process can be very labor intensive since it can entail preparing a considerable number of medication syringes that all can have different medication formulations. This also can lead to confusion and possibly human error. Finally, the human may begin withdrawing fluid from the vial before the drug is completely dissolved, especially if tired from repetitive preparations, causing the concentration to be lower than it should be or causing undissolved drug particles to be included in the syringe. This, too, presents a hazard to the patient.
If the medication needs to be reconstituted, the medication initially comes in a solid form and is contained in an injectable drug vial and then the proper amount of diluent is added and the vial is agitated to ensure that all of the solid goes into solution, thereby providing a medication having the desired concentration. The drug vial is typically stored in a drug cabinet or the like and is then delivered to other stations where it is processed to receive the diluent. As is known, the drug vial typically includes a pierceable septum that acts as a seal and prevents unwanted foreign matter from entering into the drug vial so as to contaminate the contents thereof as well as keeping the contents safely within the interior of the drug vial when the drug is stored or even during an application. The septum is typically formed of a rubber material that can be pierced by a sharp, hollow transfer device (e.g., a cannula or needle) to permit communication with the interior of the drug vial and then when the transfer device is removed the small piercing hole seals itself due to the material properties of the septum.
Typically, the medication is aspirated or otherwise withdrawn from the drug vial into a fluid conduit that can be in the form of a section of tubing or can be a cannula or a syringe. Unfortunately, one of the side effects that can occur when the medication is aspirated is that unwanted foreign particles or the like can be aspirated along with the medication into the fluid conduit. For example, the foreign particles can be in the form of particles of undissolved drug, dislodged particles of the septum, or any other foreign matter that may have found its way into the drug vial. Since the aspirated drug is intended for use in an application to a patient, the unwanted foreign matter can potentially pose a safety risk or at the very least is a sign of contamination of the drug delivery process and can raise other issues about the overall reliability. In addition, a unit dose of medication is carefully measured out for the patient and therefore, the presence of foreign matter reduced the overall volume of drug that is measured and delivered to the patient. In other words, the actual amount of drug that is dispensed is less than the apparent amount that is aspirated due to the presence of the foreign matter. Moreover and at the very least, the presence of foreign matter constitutes a contamination of the unit dose and often requires that the unit dose be discarded. This results in waste of the drug and increases the overall cost of the drug.
What is needed in the art and has heretofore not been available is a system and method for automating the medication preparation process and more specifically, a safety and cost reducing feature that is capable of detecting unwanted foreign matter that may be present in a unit dose of medication that is withdrawn from a drug vial.